Fluid-operated timers are well-known devices. Generally, a fluid-operated timer is a device which utilizes a "control fluid" to determine or measure a period of time. A fluid-operated timer can be mechanically coupled to a valve such that when a preselected period of time elapses the timer causes the valve to either open or close, thereby regulating the flow of a fluid. As recognized by those skilled in the art, a portion of the regulated fluid can be used as the control fluid for the timer. The present invention is generally directed to such a fluid-operated timer.
The control fluid or regulated fluid associated with a fluid-operated timer could be a liquid or a gas. The present invention, however, is particularly directed to a liquid-operated timer which is mechanically coupled to a valve suitable for controlling the flow of a liquid, wherein a portion of the regulated liquid is used as the control liquid.
A preferred embodiment of the invention is a hydraulic timer apparatus which is coupled to a hydraulic valve suitable for controlling the flow of water from a source to a utilization point. The preferred timer apparatus stops the flow of the regulated liquid after a predetermined period of time.
At least two hydraulic mechanisms have been used to prevent the flow of a liquid through a conduit after a predetermined period: (i) float valves and (ii) restricted return flow valves. A float valve utilizes a tank and float wherein the tank retains fluid and the increasing amount of fluid retained supports and moves the float upward. The float is operatively engaged to a normally-open valve such that when the float has risen a preset distance the valve is closed. An example of this type of timer valve is described in U.S. Pat. No. 2,973,781. The liquid which is subject to control by the normally-open valve is the same liquid which is accumulated by the tank and used to close the valve. One disadvantage associated with this type of valve is that the liquid must be manually drained from the tank in order to reset the valve for a subsequent operation.
A restricted return flow valve includes a normally-closed valve which is manually opened. Return of the valve to its normally-closed position is impeded by a fluid which enters a chamber when the valve is manually opened. The valve closes when the chamber fluid is forced out of the chamber through an orifice. An example of this type of hydraulic timer valve is shown in U.S. Pat. No. 2,549,909. One perceived disadvantage of this type of timer valve is that it must be manually actuated in order to open the normally-closed valve and initiate the timing process.
In some situations it is desirable to have a timer valve which is entirely automatic in that it can cycle repeatedly without requiring human intervention. Thus, one of the drawbacks associated with prior art hydraulic timers is that they must be manually actuated or reset for each operation.
In an attempt to address this problem, automatic electrical timers have been utilized to regulate the flow of a fluid through a conduit. Such timers are certainly capable of completely automatic actuation and reset. However, electrical timers also have drawbacks which include: (1) they are difficult to install and repair as they must be connected to a source of electricity; (2) they are relatively expensive compared to hydraulic timers; and (3) they are safety hazards, especially when used near water.
Therefore, a substantial need exists for a simple, safe, completely automatic mechanical hydraulic timer valve. Such a valve could be advantageously utilized to control the amount of a liquid allowed to flow through and contat a cleaning chemical.
This need is fulfilled by the hydraulic timer of the present invention. It automatically and mechanically (not electrically) actuates upon the onset of flow of the regulated liquid and automatically and mechanically resets when the flow of regulated liquid through the hydraulic timer valve is shut off.